In recent years, disk devices such as magnetic disk drives, and optical disk drives are widely used as external recording devices or image recording devices of computers.
A disk device, for example, a magnetic disk drive is generally provided with a magnetic disk arranged in a casing, spindle motor configured to support and rotationally drive the magnetic disk, and head gimbal assembly (HGA) supporting a magnetic head. The head gimbal assembly includes a suspension attached to a distal-end portion of an arm, flexure (conductive trace member) provided on the suspension, and drawn out from the suspension, and a magnetic head supported on the suspension through a gimbal-portion of the flexure. Traces of the flexure are electrically connected to the magnetic head. Further, the suspension includes a load beam, and base plate fixed to a proximal end of the load beam. The base plate is fixed to the distal-end portion of the arm.
In recent years, there is proposed an HGA in which a thin-film piezoelectric (PZT) element is mounted on the gimbal-portion of a flexure, and infinitesimal displacement of the magnetic head in the seek direction is created by the expansion/contraction motion of the piezoelectric element. According to the HGA, it becomes possible to control an operation of the magnetic head by controlling a voltage to be applied to the piezoelectric element.
However, in the HGA described above, when the piezoelectric element is expanded or contracted by voltage application, the piezoelectric element is bent in the thickness direction thereof. Accordingly, part of the expansion or contraction of the piezoelectric element escapes in the direction in which the piezoelectric element is bent, and the displacement of the magnetic head is reduced. Thereby, it becomes difficult to obtain a displacement control amount of the magnetic head corresponding to the displacement amount of the piezoelectric element. In order to obtain the desired displacement control amount, a piezoelectric element of a greater size is required, and hence problems are caused in terms of the manufacturing cost and size reduction of the HGA.